Currently computers have several input devices or interfaces which operators use to initiate or terminate computing tasks, to interrogate the computer to determine the status of tasks during execution, or to give and receive instructions. One interface is a computer keyboard. The keyboard is a relatively slow input device. The keyboard includes a typing pad and a number pad that a human operator uses to input various data and commands. Another computer input device is a mouse. The mouse has the advantage of speed, convenience and control. The mouse typically includes a ball within a housing. The housing has a semispherical cavity. A ball fits within the semispherical cavity. In the wall of the cavity are several built-in motion detectors which detect the motion of the ball when it is rolled. The motion detectors are actually two rollers mounted at 90-degree angles with respect to each other, which ride on the surface of the ball. Attached at one end of each roller is a wheel, known as an encoder. The wheel has openings near the outer periphery. A light-emitting diode is on one side of the wheel and on optical pickup is on the other. As the ball moves, the roller-attached wheel turns and produces a flash of light at the optical pickup. Each time an optical pickup detects light, an electrical signal results. The number of signals produced indicates the number of openings on the encoder that have been passed. Typically, there are two rollers with encoders. One roller indicates vertical movement and the other roller indicates horizontal movement of the cursor. The direction in which the rollers are turning, combined with the ratio between the number of signals from the vertical and horizontal rollers, indicate the direction that the mouse is moving. The signals from the two encoders are transferred to a microprocessor. The microprocessor converts the signals to movement of a cursor on the computer screen. Side to side movement of the mouse converts to horizontal movement on the computer screen. Movement of the mouse toward and away from the computer converts to vertical movement on the computer screen.
The mouse also includes buttons. Most mouse input devices have two mouse buttons, although, some have only one and others have more. The buttons are mounted on the housing of the mouse so that they are easily clicked using the user's finger. By clicking one or more buttons atop the mouse, additional input signals are sent to the computer. A single tap to a right mouse button moves the blinking cursor to a selected point on the screen. Large areas of the screen can be marked by "clicking and dragging." In other words, by depressing a mouse button and moving the mouse over a surface, large areas can be marked.
Another input device is a trackball. A trackball is essentially a mouse in an upside-down orientation. The ball of a trackball is mounted so that the ball is rotated by the user's fingers instead of along a flat surface of the user's desk or along a mouse pad. Other input devices include joysticks and yokes. Joysticks and yokes are typically used for controlling game software.
Mouse devices and trackballs have shortcomings. First of all, they are electromechanical devices and require mechanical interaction between the ball and the roller in order to work. Mechanical devices are generally more prone to failure than an electrical device. Another problem is that a mouse or a trackball can get dirty over time. Dust and other material can collect in the spherical housing of the mouse or trackball which causes the roller to roll erratically or not to roll at all. Periodic cleaning is then required. Another problem is that mouse devices require desktop space. When using a smaller computer, such as a notebook or portable computer, many times desktop space is unavailable. One such place where desktop space is unavailable is on an airplane, train or bus. The mouse or trackball typically also has cabling which can be cumbersome in limited desktop space applications. Some input devices now communicate via infrared or radio signal to eliminate the cumbersome cables.
In notebooks and portables, trackballs have been incorporated into the keyboard to lessen the need for desk space. Trackballs add space to the keyboard of a notebook or portable computer. It is desirable to make notebook computers as small as possible and adding a trackball limits the amount of reduction that can be accomplished. The trackballs still are mechanical and prone to mechanical failure as well as getting dirty. Touch pads are also now being incorporated into the keyboard. These also limit how small the notebook can be made. Small, short joysticks have also been used to move a cursor. Small short joysticks, touch pads and trackballs all require separate buttons for inputting additional signals to the computer. Most of these input devices also have some mechanical portion which may be prone to failure. The small, short joysticks, touch pads and trackballs also require movement which is not the same as the movements associated with using a mouse; therefore a user familiar with a mouse must learn new movements in order to use these input devices.
U.S. Pat. No. 5,059,959 includes a cursor-aiming system for use with a screen having a movable cursor. A field is generated and the cursor on the screen moves in response to the movement of an operator's finger within the field. This patent eliminates some of the mechanical components but still has a number of shortcomings. The field, as shown in the patent, is not positioned beside the keyboard where a mouse pointing device would normally be. In addition, the field is not positioned over the keys of the keyboard where a short pointing device or a built in track ball would normally be used. As a result, an operator could not just merely use finger motions within the same volume where finger motions for a previous input device were used. The field in U.S. Pat. No. 5,059,959 is positioned over the front of the keyboard and appears to be positioned in front of the screen in a computer system. As a result, the operator repositions ". . . a cursor on a screen on a computer terminal display by lifting a forefinger from the keyboard and moving the finger in the desired direction of cursor movement." (Column 5, lines 26-29 of U.S. Pat. No. 5,059,959). U.S. Pat. No. 5,059,959 seems to be a touchless screen input device where the field remains essentially in one volume. U.S. Pat. No. 5,059,959 is limited to moving the cursor and does not teach other motions which could be interpreted as other inputs. As a result, the operator must relearn a new set of finger motions or, more than likely, go back to keyboard commands or use an additional input device to input information into the computer. An additional drawback is that two hands must be used to input commands into the computer using the device taught in U.S. Pat. No. 5,059,959. To prevent unintentional hand or finger motions from affecting the cursor, ". . . the apparatus is normally deactivated and the operator must enable it when desired by holding down a control key with one hand while gesturing with the other." (Column 5, lines 30-34 of U.S. Pat. No. 5,059,959).